The role of the microbiome in drug resistance in gastrointestinal cancers.

Introduction: The microbiota is recognized for its impact on both human health and disease. The human microbiota is made up of trillions of cells, including bacteria, viruses, and fungi. The largest population of microbes reside in the gut, prompting research for better understanding of the impact of gastrointestinal microbiota in different diseases. Evidence from numerous studies has pointed out the role of commensal microbes as key determinants of cancer pathogenesis. Moreover, gut microbiota may play an important role in chemoresistance; consequently, this knowledge might be important for novel strategies to improve anticancer treatment efficacy. Areas covered: We describe the role of microbiota in different gastrointestinal cancer types (esophageal, gastric, colorectal, hepatocellular and pancreatic-biliary tract cancers). Moreover, we analyzed the impact of the microbiota on resistance to anticancer therapies, and, lastly, we focused on possibilities of microbiota modulation to enhance anticancer therapy efficacy. Expert opinion: Increasing evidence shows that gut microbiota might influence resistance to anticancer treatment, including conventional chemotherapy, immunotherapy, radiotherapy, and surgery. Therefore, a better knowledge of gut microbiota and its interactions with anticancer drugs will enable us to develop novel anticancer treatment strategies and subsequently improve the cancer patients' outcome

The role of gut microbiota: from gastrointestinal cancer to neurodegenerative diseases

The intestinal milieu harbours the gut microbiota, consisting of a complex community of bacteria, archaea, fungi, viruses and protozoans that bring to the host organism an endowment of cells and genes more numerous than its own. In recent years, an interest in intestinal microbiota-host interactions has increased due to many findings about the impact of gut bacteria on human health and disease. Gut microbiota dysbiosis, defined as marked alterations in the amount and function of the intestinal microorganisms, is correlated with the aetiology of chronic diseases, ranging from cardiovascular, neurologic, respiratory and metabolic illnesses to cancer. In this review, we focus on the interplay among gut microbiota and host to provide a perspective on the role of microbiota in the pathogenesis and progression of various human disorders, highlighting the influence of gut microbiota on cancers in the gastrointestinal tract and on neurodegenerative diseases

The human microbiota and prostate cancer: Friend or foe?

The human microbiome is gaining increasing attention in the medical community, as knowledge on its role not only in health but also in disease development and response to therapies is expanding. Furthermore, the connection between the microbiota and cancer, especially the link between the gut microbiota and gastrointestinal tumors, is becoming clearer. The interaction between the microbiota and the response to chemotherapies and, more recently, to immunotherapy has been widely studied, and a connection between a peculiar type of microbiota and a better response to these therapies and a different incidence in toxicities has been hypothesized. As knowledge on the gut microbiota increases, interest in the residing microbial population in other systems of our body is also increasing. Consequently, the urinary microbiota is under evaluation for its possible implications in genitourinary diseases, including cancer. Prostate cancer is the most common cancer in the male population; thus, research regarding its etiology and possible factors correlated to disease progression or the response to specific therapies is thriving. This review has the purpose to recollect the current knowledge on the relationship between the human microbiota and prostate cancer

Modulation of Gut Microbiota in Pathological States

The human microbiota is an aggregate of microorganisms residing in the human body, mostly in the gastrointestinal tract (GIT). Our gut microbiota evolves with us and plays a pivotal role in human health and disease. In recent years, the microbiota has gained increasing attention due to its impact on host metabolism, physiology, and immune system development, but also because the perturbation of the microbiota may result in a number of diseases. The gut microbiota may be linked to malignancies such as gastric cancer and colorectal cancer. It may also be linked to disorders such as nonalcoholic fatty liver disease (NAFLD); obesity and diabetes, which are characterized as “lifestyle diseases” of the industrialized world; coronary heart disease; and neurological disorders. Although the revolution in molecular technologies has provided us with the necessary tools to study the gut microbiota more accurately, we need to elucidate the relationships between the gut microbiota and several human pathologies more precisely, as understanding the impact that the microbiota plays in various diseases is fundamental for the development of novel therapeutic strategies. Therefore, the aim of this review is to provide the reader with an updated overview of the importance of the gut microbiota for human health and the potential to manipulate gut microbial composition for purposes such as the treatment of antibiotic-resistant Clostridium difficile (C. difficile) infections. The concept of altering the gut community by microbial intervention in an effort to improve health is currently in its infancy. However, the therapeutic implications appear to be very great. Thus, the removal of harmful organisms and the enrichment of beneficial microbes may protect our health, and such efforts will pave the way for the development of more rational treatment options in the future

The human gastrointestinal microbiota and prostate cancer development and treatment

The human gastrointestinal microbiome contains commensal bacteria and other microbiota that have been gaining increasing attention in the context of cancer development and response to treatment. Microbiota play a role in the maintenance of host barrier surfaces that contribute to both local inflammation and other systemic metabolic functions. In the context of prostate cancer, the gastrointestinal microbiome may play a role through metabolism of estrogen, an increase of which has been linked to the induction of prostatic neoplasia. Specific microbiota such as Bacteroides, Streptococcus, Bacteroides massiliensis, Faecalibacterium prausnitzii, Eubacterium rectalie, and Mycoplasma genitalium have been associated with differing risks of prostate cancer development or extensiveness of prostate cancer disease. In this Review, we discuss gastrointestinal microbiota’s effects on prostate cancer development, the ability of the microbiome to regulate chemotherapy for prostate cancer treatment, and the importance of using Next Generation Sequencing to further discern the microbiome’s systemic influence on prostate cancer

Beneficial modulation of the gut microbiota

peer-reviewedThe human gut microbiota comprises approximately 100 trillion microbial cells and has a significant effect on many aspects of human physiology including metabolism, nutrient absorption and immune function. Disruption of this population has been implicated in many conditions and diseases, including examples such as obesity, inflammatory bowel disease and colorectal cancer that are highlighted in this review. A logical extension of these observations suggests that the manipulation of the gut microbiota can be employed to prevent or treat these conditions. Thus, here we highlight a variety of options, including the use of changes in diet (including the use of prebiotics), antimicrobial-based intervention, probiotics and faecal microbiota transplantation, and discuss their relative merits with respect to modulating the intestinal community in a beneficial way.C.J.W, C.M.G. and P.D.C are supported by a SFI PI award “Obesibiotics” (11/PI/1137

Microbiota: the missing link in the etiology of inflammatory bowel disease

Within its twisted and tight walls, where a hostile and arid environment prevails, the lumen of the digestive tract nests a true microuniverse called the microbiota. The existing relationship between humans and these microorganisms is one in which both benefit, creating a condition called Eubiosis. The dynamic relationship existing between the microbiota and the human body can be affected at various times, leading to an imbalance that may have important implications on health and generating a condition called Disbiosis. Recent studies have highlighted possible links between several diseases with incompletely elucidated etiology and disturbances of the microbiota. In this review we aim to analyze the existing relationship between the imbalances of the gastrointestinal flora and the etiopathogeny inflammatory bowel diseases, a group of diseases whose incidence has increased considerably in recent years

Chronic Stress, Inflammation, and Colon Cancer: A CRH System-Driven Molecular Crosstalk.

Chronic stress is thought to be involved in the occurrence and progression of multiple diseases, via mechanisms that still remain largely unknown. Interestingly, key regulators of the stress response, such as members of the corticotropin-releasing-hormone (CRH) family of neuropeptides and receptors, are now known to be implicated in the regulation of chronic inflammation, one of the predisposing factors for oncogenesis and disease progression. However, an interrelationship between stress, inflammation, and malignancy, at least at the molecular level, still remains unclear. Here, we attempt to summarize the current knowledge that supports the inseparable link between chronic stress, inflammation, and colorectal cancer (CRC), by modulation of a cascade of molecular signaling pathways, which are under the regulation of CRH-family members expressed in the brain and periphery. The understanding of the molecular basis of the link among these processes may provide a step forward towards personalized medicine in terms of CRC diagnosis, prognosis and therapeutic targeting